As imaging devices become lighter and smaller, the images captured by such devices are more susceptible to quality degradation due to inadvertent shaking. In still image capture, the shake may result in a blurry image. In video capture, the shake may result in shaking or jitter in the video image. Shake and jitter can make it difficult for the human visual system to focus and concentrate on a region or object of interest within the video. When this shake appears in conjunction with genuine motion in the video, the adverse effects can be compounded. In either case, the quality of the viewing experience of the video or image is reduced.
Image stabilization systems attempt to compensate images for shaking to produce better image quality. Image stabilization systems generally fall into three main categories: optical image stabilizers (OIS), mechanical image stabilizers (MIS), and electronic image stabilizers (EIS). OIS systems employ an adjustable lens that morphs the image before it reaches the sensor, with the lens being controlled by an external motion sensor. MIS systems stabilize the entire camera and not the image captured by the camera. In particular, MIS systems typically use the center of gravity of the camera, a counterbalance system, and the camera operator's body to maintain smooth motion.
EIS systems employ signal processing algorithms to alter the captured image. Some EIS systems work well in many situations, but may suffer from an inability to differentiate genuine motion from unwanted shaking. Zooming EIS involves increasing the size of a captured image by zooming, and then zooming within the image to select a slightly smaller image that compensate for movement caused by shaking. Oversized EIS involves capturing an image slightly larger than a required resolution, and panning within the over-sized image to compensate for movement caused by shaking.